Dental handpiece



July 1, 1969 L 3,452,438

DENTAL HANDPIECE Filed Sept. 6. 1966 Sheet /7 I I l/ m Mum me MAM/c5 A04 y July 1, 1969 LORY 3,452,438

DENTAL HANDPIECE Filed Sept. 6, 1966 Sheet 3 of 2 hwavro:

MAl/P/CE Lazy United States Patent 3,452,438 DENTAL HANDPIECE MauriceLory, Paris, France, assignor to Etablissements E. Quetin, Paris,France, a corporation of France Filed Sept. 6, 1966, Ser. No. 577,266Claims priority, applicaotiog France, Sept. 7, 1965, 3 7 0 Int. Cl. Am1/00 US. C]. 32-28 1 Claim ABSTRACT OF THE DISCLOSURE The presentinvention refers to portable dentist drills of the kind comprising amotor incorporated within a portable casing for cooperating at thechoice of the practitioner with any one of a plurality of toolholders.

Portable drills are usually fitted with a spray equip ment adapted toproduce on the operating field a jet or spray of atomized cooling fluid,normally constituted by a mixture of water and air, but which also mayinclude other fluids as disinfectants, anesthetics or others.

One of the problems encountered in such apparatuses is to heat the sprayto an appropriate temperature, generally 37 C. To this effect onealready proposed a heating system comprising a self-heating tubeinserted on the flowpath of each of the fluids to be atomized, said tubeconsisting of an electrically resistant tubular section.

Such a heating equipment is usually disposed upstream of the drillingapparatus, with the resulting disadvantage of placing it in a remoteposition from the operating field and increasing thereby the thermicinertia of the system. According to another more recent proposal theheating is arranged within the toolholder, but this arrangement involvesan alteration of all the toolholders, requiring the electric current tobe supplied within the toolholder itself, which may cause difiicultiesin certain types of toolholders.

The present invention has for object to avoid all these difliculties andessentially consists in arranging the conditioning means of the spraywithin the portable casing of the driving motor.

According to the invention there is provided an arrangement whereby thespray conditioning means are arranged within the motor casing andinclude a mixing chamber having one outlet and at least two inlets, eachof said inlets being connected to a source of fluid by a self-heatingtube incorporated into said casing.

This arrangement provides several advantages such as:

Low thermic inertia;

Regularity of the mixture realized in the mixing chamber;

Utilizing of heat eventually generated in the driving motor particularlywhen this one is an electric motor;

Possibility of working with any existing toolholders.

According to a preferred embodiment of the invention the self-heatingtubes are grouped under an insulating 3,452,438 Patented July 1, 1969sheathing in a cable wound around a support member of the driving motor.This arrangement offers the additional advantage of a particularlycompact construction, the whole heating system being integrated withinthe motor unit without increasing the overall dimension thereof.

One form of embodiment of the invention will be described hereafter withreference to the attached drawings wherein:

FIG. 1 shows a portable drilling apparatus according to the invention,partly in section;

FIG. 2 is a diagram of an electric control equipment.

Referring to FIG. 1, there is shown, in its portable casing, an electricmotor 1, and interchangeable toolholder 2 and the tool 3, as well asspraying nozzle 4, connected by a flexible piping 4A to the outlet of amixing chamber 5, this latter itself having two inlets respectivelyconnected to heating tubes 6 and 7, which are arranged in thisparticular case to warm up flows of air and water, arriving as in 6a and7a together with the electric current wiring (not shown in FIG. 1).

These electrically resistant tubes are covered with a heat resistantinsulating sheath 8, and the assembly is wound around support member 9which is also used for supporting motor 1.

This particular arrangement made possible by the very small volume takenby the tubes and their sheath allows for leading the fluids to mixingchamber 5, bringing them to the suitable temperature in a very shorttime owing to the very low thermic inertia of the system.

The self-heating tubes 6 and 7 are constituted for example each by asection of a length of about twenty centimeters of a tubular resistancewith an inner diameter of millimeter and an external diameter of Amillimeter.

FIG. 2 shows an associated electric control equipment. Motor 1 is fed byits own source of energy through a relay 10, in case of an electricmotor, or through an electrovalve in case of a hydraulic or pneumaticmotor.

This relay 10 (or this electrovalve) is controlled by the operator bymeans of switch 11.

The heating tubes 6 and 7 form two resistances connected in parallelacross secondary winding of a reducing transformer 17 with multipletappings at the primary.

By means of switches 12 and 13 and of the relay 14 the operator can atwill cut olf simultaneously the spray system (switch 12) and the heatingsystem (switch 13) the electrovalves 15 and 16, respectively controllingthe admission of the fluids in heating tubes 6 and 7.

The regulation of the temperature is effected either by the selection ofthe transforming ratio of the transformer, or by any other equivalentmeans.

The voltage provided by the secondary of the transformer being only of afew volts and the circuit of the tubes 6 and 7 of course being connectedto earth, all risk of incident or accident by electric shock for thepatient or the operator is eliminated.

What I claim is: 1. Dentist drill apparatus comprising: a portablecasing, a driving motor incorporated within said casing, a toolholderinterchangeably adaptable to said casing, a spray nozzle on saidtoolholder, a mixing chamber for mixing air and water within said casinghaving an outlet and at least two inlets, one for air and the other forwater,

3 4 an external conduit connecting said nozzle to said outfluid and of areducing transformer feeding the heatlet for supplying mixed air andwater to said outlet, ing resistances constituted by said self-heatingconfor each of said inlets, a self-heating conduit consisting duits.

of an electrically resistant tube sectionmcorporated References Citedwithin said casing and connecting said inlet to a 5 Source f fl idUNITED STATES PATENTS and an electric control equipment comprising, froman 3,254,646 6/1966 Staunt et a1. 128173.1 electric source, a motorcontrol circuit and a spray 3 346,958 10/1967 Sinatra et a1, 32-28control circuit, a common switch for both circuits, the second of whichcomprising the grouping in 10 ROBERT PESHOCK, Primary Examiner. parallelof electrovalves each controlling a flow of

